But we don't have UKIP and BNP as our big parties; instead we have three main parties that have moved closer and closer in recent years. At a distance, the Tories, Lib Dems, and Labour, look quite similar, inhabiting a political centre-ground, with policies on taxation and spending only varying by a few percentage points.

I don't think a change to AV would do anything to change this; indeed, the suggested need for candidates to work harder to appeal across the electorate might accelerate this move towards the centre.

I'd prefer a genuine distinction between our parties, particularly on economic matters. Only the crackpot socialist parties (BNP, Greens) are breaking away from the received wisdom on taxation. We ought to have more choice across the political spectrum.